Which of these is an example of an overcurrent protection device?

• A. Fuses or circuit breakers
• B. GFCI
• C. Surge protector
• D. Bonding jumper

Answer: (A)

Overcurrent protection devices automatically stop current when it exceeds a safe level to prevent overheating and fire in conductors and equipment. Fuses and circuit breakers are designed for this purpose: a fuse contains a metal element that melts when the current is too high, opening the circuit, while a circuit breaker trips (via a thermal or magnetic mechanism) to interrupt the current. GFCIs protect people from shock by detecting an imbalance between hot and neutral, not by limiting current in normal operation. Surge protectors guard against voltage spikes and may include some protection features, but their primary job isn’t to interrupt overcurrent in a circuit. Bonding jumpers are part of grounding/bonding practices and do not function as protective current-interrupting devices. Hence, the clear example of an overcurrent protection device is fuses or circuit breakers.